1/2 inch female BSP thread. WELS is not relevant to tap equipment used exclusively over a bath or spa.Designers have concentrated their attention on the joint between the vertical and horizontal elements. As in nature, there are no cuts and weldings, so that the spout and handle have a soft connection to the body. This item is in the category "Home & Garden\Bath\Showers, Baths & Parts\Bath Taps & Thermostats". The seller is "mitobathrooms" and is located in this country: AU. This item can be shipped worldwide.